Re: Solver Stagnated?

On Thu, Jun 5, 2008 at 2:12 PM, Zhiwen Liang <liangz@...> wrote:
> Hi Daniel,
> I got the following error when I am running simulations with Fipy:
> Stagnated SolverWarning: The solver stagnated.
> It happens at some time steps and then goes normal and may happen again. Do
> you know what is the reason?

I would assume that it indicates that the solver is iterating without
reducing the residual significantly. I may be wrong. Maybe the system
is poorly conditioned. This can happen for fourth order problems with
large grids. I have been using the preconditioners in trilinos  (a
solver package from Sandia) to help with this problem. Obviously, this
is just speculation as I have no idea what you're solving.

Cheers

--

-- 
Daniel Wheeler